Clever nowadays at pet management (5)
I believe the answer is:
adept
'clever' is the definition.
(adept can mean clever or expert)
'nowadays at pet management' is the wordplay.
'nowadays' becomes 'AD' (AD, Anno Domini, as opposed to BC, Before Christ).
'at' is a charade indicator (letters next to each other).
'management' indicates anagramming the letters.
'pet' anagrammed gives 'ept'.
'ad'+'ept'='ADEPT'
(Other definitions for adept that I've seen before include "efficient" , "Master" , "Dexterous" , "Skillful" , "One who is very skilful" .)